If your load is fairly constant, maintaining your own servers is cheaper from the moment where you need two physical servers. And even at Netflix scale "maintain their own datacenter" might mean renting a few racks in a data center of your choice.
The arguments for cloud look different: services offered by the cloud providers, higher flexibility, no capex (though at small scale you can rent and at Netflix scale capex is presumably not an issue) or better scaling in highly variable loads.
Netflix encoding servers probably have very variable load since releases vary depending on season (like the flood of films for Christmas).
I'v e found that "your own servers" vs. "rent a cloud" are a bit weird as a company grows. First one is cheaper, then the other, then the first one again, then the other again, it continues like this a few times.
At one point it's quite possible that a combination of the two is the cheaper option.
And yes, you're completely right, load variability plays a huge role in all this.
That is very odd and doesn't mesh with my experience at all. Usually the server cost is linear with growth (more or less) so if the per unit cost is fixed (more or less) then how on earth would such a swap occur.
Depends on the size. When operating your own servers, you need to recreate all that cloud providers do for you:
- maintain the physical machines
- build or rent data centers
- have people to operate, maintain, upgrade the machines
- set up, build, maintain, update, upgrade infrastructure for your projects to work on your machines
All these costs are not insignificant when you need more and more machines. And as it was mentioned above, they don't do well when demand is variable: when you no longer need as many machines, you can't just decommission them. When demand spikes, you can't install new servers instantly.
Hybrid approach brings its own problems: your software and your infra has to work on your own servers and in the cloud, which is a harder feat to pull off than it seems.
The arguments for cloud look different: services offered by the cloud providers, higher flexibility, no capex (though at small scale you can rent and at Netflix scale capex is presumably not an issue) or better scaling in highly variable loads.
Netflix encoding servers probably have very variable load since releases vary depending on season (like the flood of films for Christmas).